This invention relates to systems and processes for cleaning, chemical sterilizing or disinfecting medical devices.
Medical instruments have traditionally been sterilized or disinfected using either heat, such as is provided by steam, or a chemical in liquid, gas, or vapor state. Prior to sterilization or disinfection, the instruments to be treated are usually first cleaned. After sterilization or disinfection with a liquid chemical germicide, purified water is used to rinse the instruments, and then the instruments are dried. Numerous publications regarding the cleaning of medical devices and the sterilizing of medical devices are available.
U.S. Pat. No. 5,443,801 discloses a transportable cleaning/sterilizing apparatus and method for inside-outside washing and sterilization of medical/dental instruments. The apparatus functions in four sequential cycles: wash, rinse, sterilize, and dry. The sterilization step is conducted using ozonated and purified water, and the drying step is accomplished by injecting ozonated/deozonated sterile warm dry oxygen, or sterile inert gas into and exhausted from the wash chamber under a positive pressure relative to atmospheric. In this process, the device has to be rinsed with purified water after it is sterilized to remove sterilant residue before drying step.
U.S. Pat. No. 5,505,218 to Steinhauser et al. discloses a device for cleaning, disinfecting and maintaining medical or dental instruments. The device has a pot-shaped container with a multiplicity of mountings in the interior of the container each for one of tool holder, a water supply system, a compressed air supply system, and an ultrasonic transducer, The disinfection is conducted with heated water, and the drying is conducted with hot compressed air. This system is not designed for sterilization.
U.S. Pat. No. 5,279,799 to Moser et al. discloses apparatus for cleaning and testing endoscopes by injecting pressurized air into the sheath and pressurized air and washing liquid into the ducts. A washing chamber is provided which contains retractable cages to hold the endoscopes during cleaning and testing. This process includes washing, disinfecting, final rinsing with purified water, and air drying the ducts of a tubular article. A number of filters are involved in this system, and this system is not designed for sterilization.
U.S. Pat. No. 4,744,951 to Cummings et al. discloses a two-chambered system that provides hydrogen peroxide in vapor form for use in sterilization processes. The sterilant is initially vaporized in one chamber and then applied to the object to be sanitized in another single sterilizing chamber, thereby producing a concentrated hydrogen peroxide vapor which is relatively more effective. The sterilization processes are designed for furnishing concentrated hydrogen peroxide vapor to interior surfaces of articles having a tortuous or a narrow path. However, the sterilization processes are ineffective at rapidly sterilizing lumen devices, since they depend on the diffusion of the hydrogen peroxide vapor into the lumen to effect sterilization.
U.S. Pat. No. 4,863,688 to Schmidt et al. discloses a sterilization system consisting of a liquid hydrogen peroxide vaporization chamber and an enclosure for sterilization. The enclosure additionally may hold containers wherein the hydrogen peroxide sterilant vapor does not contact the interior of the containers. This system is designed for controlling the exposure to the hydrogen peroxide vapor. The system is not designed for sterilizing a lumen device.
U.S. Pat. No. 4,943,414, entitled xe2x80x9cMethod for Vapor Sterilization of Articles Having Lumens,xe2x80x9d and issued to Jacobs et al., discloses a process in which a vessel containing a small amount of a vaporizable liquid sterilant solution is attached to a lumen, and the sterilant vaporizes and flows directly into the lumen of the article as the pressure is reduced during the sterilization cycle. This system has the advantage that the water and hydrogen peroxide vapor are pulled through the lumen by the pressure differential that exists, increasing the sterilization rate for lumens, but it has the disadvantage that the vessel needs to be attached to each lumen to be sterilized.
U.S. Pat. Nos. 4,937,046, 5,118,471 and 5,227,132 to Anderson et al. each disclose a sterilization system that uses ethylene oxide gas for sanitation purposes. The gas is initially in a small first enclosure and thereafter slowly permeates into a second enclosure where the objects to be sterilized are located. A medium is then introduced into the second enclosure to flush out the sterilizing gas into a third enclosure containing the second enclosure. An exhaust system then exhausts the sterilant gas and air from the third enclosure. These systems also have the disadvantage of relying on the diffusion of the sterilant vapor to effect sterilization and hence are not suitable for rapidly sterilizing lumen devices.
U.S. Pat. No. 5,122,344 to Schmoegner discloses a chemical sterilizer system for sterilizing items by vaporizing a liquid chemical sterilant in a sterilizing chamber. Pre-evacuation of the sterilizer chamber enhances the sterilizing activity. Sterilant is injected into the sterilizer chamber from a second prefilled shot chamber. This system also relies upon diffusion of sterilant vapor to effect sterilization and is also not suitable for rapidly sterilizing lumen devices.
U.S. Pat. No. 5,266,275 to Faddis discloses a sterilization system for disinfecting instruments. The sterilization system contains a primary sterilization chamber and a secondary safety chamber. The secondary safety chamber provides for sensing and venting to a destruction chamber any sterilization agent that is released from the primary sterilization chamber. This system, as in other systems, also relies upon diffusion of sterilant vapor to effect sterilization and is also not suitable for rapidly sterilizing lumen devices.
In U.S. Pat. Nos. 5,492,672 and 5,556,607 to Childers et al, there is disclosed a process and apparatus respectively for sterilizing narrow lumens. This process and apparatus uses a multicomponent sterilant vapor and requires successive alternating periods of flow of sterilant vapor and discontinuance of such flow. A complex apparatus is used to accomplish the method. Additionally, the process and apparatus of ""672 and ""607 require maintaining the pressure in the sterilization chamber at a predetermined subatmospheric pressure.
In U.S. Pat. No. 5,527,508 to Childers et al., a method of enhancing the penetration of low vapor pressure chemical vapor sterilants into the apertures and openings of complex objects is disclosed. The method repeatedly introduces air or an inert gas into the closed sterilization chamber in an amount effective to raise the pressure to a subatmospheric pressure to drive the diffused sterilant vapor further into the article to achieve sterilization. The ""508, ""672 and ""607 Childers inventions are similar in that all three require repeated pulsations of sterilant vapor flow and maintenance of the sterilization chamber pressure at a predetermined subatmospheric pressure.
One disadvantage of the cleaning/sterilizing or cleaning/disinfecting systems of the prior art as discussed above is that, after the device is sterilized or disinfected and before it is dried, the device has to be rinsed with purified water to remove disinfectant or sterilant residues. A so-called bacteria filter is usually used to filter the water to remove particulates and bacteria. Typically, a two-stage filtering system is utilized, for example, a first stage has a 2-5 micron filter and a second stage has a 0.1-0.2 micron filter. However, virus can be smaller than 0.1 micron. This means the virus can penetrate the filtering system recontaminating the sterilized device in the final rinsing process. Another problem associated with the use of a bacteria filter is that bacteria can form biofilms in the filter which are difficult to sterilize and, thus, become a new potential source of contamination.
Thus, there remains a need for a simple and effective process and apparatus for efficiently cleaning, sterilizing or disinfecting, and drying medical devices, especially those with long narrow lumens.
One aspect of the present invention provides a cleaning/sterilizing or cleaning/disinfecting process which incorporates cleaning, sterilizing (or disinfecting) and drying of a lumen or non-lumen medical device into an integrated process, i.e. the device is cleaned, sterilized, and dried in situ in the same apparatus in a operation cycle. Especially, the sterilizing and drying are conducted simultaneously. In other words, after the device is sterilized, there is no need to further rinse the sterilized device like the prior art does. Thus, there is no need for a filtering system.
Another aspect of the present invention relates to an apparatus for cleaning, sterilizing, or disinfecting medical devices, especially devices with lumens. The apparatus comprises a container with an interface for separating the container into enclosures or compartments. The interface has an opening equipped with specially designed holder(s) for eliminating or reducing occlusion area.
Another aspect of the present invention relates to a multi-compartment container. The container has a specially designed tray for accommodating a lumen device. The tray is placed across and sealed against an interface separating the container into enclosures.
Another aspect of the invention relates to a rigid or semi-rigid container that may be shaped like an endoscope. The container has one or more interfaces that separate the container into one or more compartments. The interfaces may be sealable holders and are used for holding an endoscope and for permitting differential flow of fluid, including gas or liquid, into the lumen of the endoscope, or around the outer surface of the endoscope, for purposes of cleaning or sterilization. The container may be separable into two substantially symmetrical parts, and these parts may be attached by hinges, locks, or seals. The container may also be used for storing the endoscope after it is dried.
Still another aspect of the invention relates to a container made of flexible material, which container may be shaped like an endoscope. One or more interfaces are located along the length of the container, which interfaces may be adjusted to hold the endoscope and to allow differential flow of fluid, including gas or liquid, into the lumen of the endoscope, or around the outer surface of the endoscope, for purposes of cleaning or sterilization.
One method of the present invention for cleaning/sterilizing or cleaning/disinfecting a device having a lumen with at least two open ends comprises the steps of: a) providing a container having at least one enclosure and at least one interface separating the enclosure from the container, the interface having at least one opening thereon, b) placing the device across the opening with one open end in the container and another open end in the enclosure, c) generating a flow of a cleaning solution through the lumen to clean the inner surface of the lumen, d) generating a flow of rinse solution through the lumen to rinse the inner surface of the lumen, e) treating the device with a chemical germicide, and f) adjusting the opening in any of steps c) to e) to reduce areas on outer surface of the device which are occluded from exposure to the cleaning solution, the rinse solution, or the chemical germicide by contacting with the opening, or to expose the areas to the cleaning solution, the rinse solution, or the chemical germicide. In the method, one or more steps can be repeated. In the method, along its passage, the opening has at least two independently controllable apertures for holding and sealing the device. In the method, the step of adjusting the opening comprises opening one of the two apertures while closing the other aperture so that the areas on the outer surface of the device occluded by the two apertures are alternately exposed to the cleaning solution, the rinse solution, or the chemical germicide in step c), d), or e), respectively. The method further comprises retaining a predetermined amount of the chemical germicide in the container and enclosure and vaporizing the retained chemical germicide to sterilize (or disinfect) and dry the device under vacuum during or after step e). In the method, the sterilizing or disinfecting can be conducted under a diffusion restricted environment, or by reducing pressure to a first predetermined pressure followed by further reducing the first pressure to a predetermined second pressure, or at controlled pump-down rate. In the method, the sterility of the device can be maintained in the container and enclosure after the device is sterilized and dried. The method further comprises removably attaching the container to a vacuum system for applying vacuum to the container or enclosure and detaching the container after the device is sterilized (or disinfected) and dried. In the method, the flow through the lumen can be generated by applying a pressure higher than atmospheric pressure at one end of the lumen, or by applying vacuum to one end of the lumen device. In the method, the opening of the interface has separately controllable and movable contact points, and the adjusting step comprises controlling the contact points so that a different portion of the contact points is made in contact with the device alternately. In the method, the opening forms a seal around the device selected from the group consisting of a gas-tight seal, a tight-fitting seal, or a loose-fitting seal. In the method, a non-lumen device also can be treated together with the lumen device.
Another method for cleaning or sterilizing a device having a lumen with at least two open ends and an inner surface and outer surface comprises the steps of: a) providing a container having at least one interface separating the container into two or more compartments; b) placing the device across the interface with one open end of the device in one of the compartments and another open end in another of the compartments; and c) adjusting the interface to at least partially seal around the device, and generating a flow of a cleaning solution, rinse solution, or chemical germicide through the lumen to clean or sterilize the inner surface of the device. The method can additionally comprise the step of adjusting the interface to at least partially unseal around the device, and generating a flow of cleaning solution, rinse solution, or chemical germicide around the outer surface of the device to clean the outer surface of the device. In the method, one or more steps can be repeated. In addition, the interface can be adjusted in step c) by adjusting an adjustable aperture, or seal, that varies the relative amount of exposure of the inner surface and the outer surface of the device to cleaning solution, chemical germicide, and/or rinse solution. In the method, a non-lumen device can be treated in the container. The sterilizing process can be conducted under reduced pressure, such as by reducing the pressure within the container to a first predetermined pressure, followed by further reducing the first pressure to a predetermined second pressure. Alternatively, the sterilizing can be conducted at controlled pump-down rate. The sterility of the device can be maintained in the container after the device is sterilized. The method further comprises removably attaching the container to a pump system for applying an increased or decreased pressure to the container, and detaching the container after the device is sterilized. Fluid is forced from one compartment to another by generating a pressure differential between compartments. Such a pressure differential may result from application of positive pressure to one compartment, in which case fluid flows away from that compartment into the adjacent compartment. Alternatively, the pressure differential may result from application of negative pressure to one compartment by means of a vacuum system, in which case fluid flows toward that compartment from the adjacent compartment.
In the method, the container can be made of flexible material or materials. In one embodiment, the holder is external to the container, and in another embodiment, the holder is integrated into the wall of the container. Also, the container may be separable into two substantially symmetrical parts. xe2x80x9cSubstantially symmetrical,xe2x80x9d as applied to one part, is defined herein as being within 30% of the size of the other corresponding part, in one or more dimensions. In the method, the container can have one or more shower heads or jet heads located on its inner aspect, to permit pressurized influx of fluid for purposes of cleaning or sterilizing the device. The container can have one or more openings, or ports, to permit influx or efflux of fluid for purposes of cleaning or sterilizing the device. The method can utilize at least two independently controllable apertures for holding and sealing the device. The step of adjusting the interface can comprise opening one of the two or more apertures while closing the other aperture(s) so that the areas on the outer and inner surfaces of the device are alternately exposed to the cleaning solution, the rinse solution, or the chemical germicide in step c).
An apparatus of the present invention for cleaning/sterilizing or cleaning/disinfecting a lumen device having at least two open ends comprises a container having a fluid port for flowing and draining a fluid in and out the container. At least one enclosure is coupled with the container for receiving part of the lumen device so that one end of the lumen device is located in the enclosure and the other end of the lumen device is located in the container. An interface separates the container and enclosure, and the interface has at least one opening. At least one openable and closeable holder is sealably coupled to the opening. A source for creating a pressure difference between the two open ends to generate a flow through the lumen of the lumen device is provided. A cleaning mechanism adapted to clean the device in the container or enclosure is also provided. Preferably, the interface is removable. The holder can be a shutter. The holder can be equipped with expandable or compressible material on its contact surface with the device. In one embodiment, the holder has two plates forming a gap therebetween for passing the device, the surfaces of the plates facing the gap are equipped with expandable or compressible material. In another embodiment, two independently controllable holders are sealably arranged along the passage of the opening. Each one of the two holders comprises two plates forming a gap therebetween for passing. the device, the surfaces of the plates facing the gap are equipped with expandable or compressible material. Preferably, each of the gaps defines an elongate cross section having a longitudinal axis as viewed from a direction perpendicular to the surface of the plates, the longitudinal axis of one gap forms an angle with that of the other gap, and the two holders are placed close enough to each other for the expandable material on one holder to be brought in contact with the other holder when the expandable material is expanded. The apparatus further comprises a vacuum system, the container comprises a gas-permeable and microorganism-impermeable barrier and is detachably coupled to the vacuum system. The gas-permeable and microorganism impermeable barrier can be equipped with a valve for opening and closing gas communication between the container and the vacuum system or between the container and atmosphere through the barrier. The cleaning mechanism is selected from the group consisting of a stirrer, a liquid jet, an air jet, ultrasonics, or a bubble generator. The interface may comprise a first plate having a plurality of openings with elongate cross section, and at least two other plates forming a gap along a longitudinal direction, the plates are configured so that the longitudinal direction of the gap and the longitudinal direction of the elongate cross section of the opening form a substantially right angle. In another embodiment, the container has a first enclosure sharing with the container a first interface having a first opening and a second enclosure sharing with the first enclosure a second interface having a second opening, wherein the device is placed across the first and second interface through the first and second opening so that one open end of the device is located in the container and the other open end of the device is located in the second enclosure. In the apparatus of the present invention, the holder has multiple contact points on its inner surface for holding the device, and the contact points are separately controllable and movable.
Another apparatus of the present invention for cleaning or sterilizing a lumen device having at least two open ends comprises a container having one or more fluid port(s) for flowing a fluid in and out of the container, and at least one interface separating the container into two or more compartments; the lumen device being positioned such that one end of the lumen device is located in one of the compartments and another open end is located in another the compartment. In addition, there is at least one openable and closeable holder coupled to the interface, the holder allowing for occlusion and nonocclusion of the interface. The container may be shaped like an endoscope, and it may be made of flexible material. In one embodiment, the holder is external to the container, and in another embodiment, the holder is integrated into the wall of the container 2. The apparatus further comprises a cleaning mechanism adapted to clean the device in the container or the compartments, wherein the cleaning mechanism is selected from the group consisting of a stirrer, a liquid jet, an air jet, ultrasonics, or a bubble generator. The container may be separable into two substantially symmetrical parts, and these parts may be joined by a sealing or hinge mechanism.